1. Field of the Invention
The present invention relates to devices and methods for converting floating point numbers in one format to floating point numbers in another format. More specifically, the invention relates to devices and methods for converting IEEE-format floating point numbers into such floating point formats as the IBM, DEC, and SEL formats.
2. Related Art
Floating point conversion circuits and arithmetic units are known in the art.
For example, U.S. Pat. No. 3,193,669 to Voltin, U.S. Pat. No. 3,872,442 to Boles et al., U.S. Pat. No. 4,189,715 to Duttweiler, U.S. Pat. No. 4,413,326 to Wilson et al., U.S. Pat. No. 4,477,879 to Wong, U.S. Pat. No. 4,488,252 to Vasser, U.S. Pat. No. 4,534,010 to Kobayashi et al., U.S. Pat. No. 4,562,553 to Mattedi et al., U.S. Pat. No. 4,595,911 to Kregness et al., U.S. Pat. No. 4,631,696 to Sakamoto, and U.S. Pat. No. 4,675,809 to Omoto et al. disclose various known systems which either convert floating point numbers from one format into another, or conduct floating point operations in which one or more floating point numbers are the operands.
Known floating point conversion systems are relatively deficient in the ability to quickly convert floating point numbers of certain formats into floating point numbers of other formats. When such conversions are necessary, for example, in data processing or data transmission applications, the speed of the floating point conversion process becomes crucial to overall system throughput.
When considering hardware implementations of floating point conversion algorithms, regardless of the technology involved (TTL, ECL, etc.), there is always a need to improve processing speed so that any bottlenecks in the system are not due to basic operations such as floating point conversions.
If the conversion task is performed in serial steps in software, significant delays may occur. For example, software used to duplicate the task of converting a 32-bit single precision floating point number is achieved in approximately 20 microseconds using a microcode-driven DPU (Distributed Processing Unit), a fast bit-slice processor. In contrast, as will be described below, the 32-bit conversion is achieved on parallel data in 480 nanoseconds using TTL technology, when utilizing the hardware conversion device and method according to the present invention.
Therefore, there exists a need for an efficient, fast floating point conversion method, preferably implemented using simple hardware.